Вплив природних факторів на динаміку букового (fagus sylvatica L.) пралісу Українських карпат

Virgin forest is supposed to be the most sustainable ecosystem to existing in this natural zone disasters. This publication analyses the impact of the 2007 windfall and climate warming on the structural elements of the virgin forest ecosystem. The object of our research was a 10 hectares massif (200×500 m) of Common beech (Fagus sylvatica L.) virgin forest, which was divided on forty (50×50 m = 0.25 ha) research plots. There were four inventories on all 40 plots in 2000, 2005, 2010 and 2015. Inventory methods were: measuring and mapping of all trees (DBH ≥ 6 cm, living and dead); measuring of lying deadwood (D ≥ 8 cm, length ≥ 2 m) volume for degrees of decay; measuring of undergrowth (DBH < 6 cm, H ≥ 10 cm) number for height groups. The dynamics of main parameters of the beech virgin forest after the catastrophic wind influence is not the same. The largest fluctuations are typical for the tree number – after the 10 % loss of trees in 2007 the tree density increased in 2010 on 6 %, and in 2015 – on 59 %. There is 9 % annual increasing of tree number in the virgin forest during 8 years after windfall. The volume of a deadwood substantially increased – on 41 and 6 % respectively in 2010 and 2015. The undergrowth number substantially decreased – respectively on 19 and 14 %. The decrease in the wood volume of the virgin forest was already lower (respectively 7 and 4 %), while the decrease in the basal area was not significant (respectively 4 and 2 %). The diameter distribution in the beech virgin forest was constantly changing during these 15 years, but the type of the distribution remains declining, that is typically for uneven-age forests. In 2005 changes in the tree number within diameter classes fluctuated up to 25 per cent, and after windfall the magnitude of these fluctuations increased to ± 50 %. These quantitative changes made it possible to prepare a basic scheme for the influence of strong winds on the virgin forest and to set the time stages of this interaction. Diameter increment increasing defined in the beech virgin forest as a consequence of climate warming, but the windfall influence does not allow determining that clear.Міжнародні дослідження 15-річної динаміки букового пралісу проведено на 10-гектарному стаціонарному дослідному об'єкті в Угольському масиві Карпатського біосферного заповідника. Проаналізовано вплив вітровалу 2007 р. та потепління клімату на структурні елементи екосистеми пралісу. Виявлено достовірні зміни окремих показників пралісу внаслідок сильного впливу вітру: найбільші коливання характерні для густоти дерев – після втрати 10 % (у 2007 р.) вже в 2010 р. густота збільшилася на 6, а в 2015 р. – на 59 %; істотно зріс і запас мертвої деревини (відповідно на 41 та 6 %); відносне зменшення найбільшим було для кількості підросту (на 19 та 14 %); зменшення запасу деревини було вже меншим (на 7 і 4 %); зменшення суми площ поперечного перетину було неістотним (на 4 і 2 %). Аналіз реакції букового пралісу на сильний вплив вітру підтверджує гіпотезу про максимальну стійкість таких лісових екосистем до стихійних явищ, а ідентифіковані кількісні зміни дали змогу розробити принципову схему сильного впливу вітру на праліс. Дискусійним залишається питання збільшення приросту за діаметром під впливом потепління клімату – у 2010 і в 2015 рр. воно було достовірним для більшості ступенів товщини, але на його динаміку вплинув також і вітровал через зрідження намету

Novel SnO₂ based optical sensor for detectin of low ammonia concentration in water at room temperatures

In the work, presented are preliminary experimental results on the capability of a metal oxide (MO) based optical sensor to perform ammonia detection in water environment at room temperature. The electro-spray pyrolysis technique was used to deposit SnO₂ films on the distant end of standard silica optical fiber (SOF). Reflection spectra of the studied samples were preliminarily characterized in the range of 1520 to 1620 nm by using a tunable laser and an optical spectrum analyzer. Single wavelength reflectance measurements were carried out to test the sensing performances for detecting the ammonia of concentration from 4 to 20 ppm. High sensitivity to the target analyte and fast response times were observed. From the results obtained, the detection limit close to a sub-ppm level was achieved

Influence of PDA Coating on the Structural, Optical and Surface Properties of ZnO Nanostructures

Polydopamine (PDA) is a new biocompatible material, which has prospects in biomedical and sensor applications. Due to functional groups, it can host wide range of biomolecules. ZnO nanostructures are well known templates for optical sensors and biosensors. The combination of ZnO and PDA results in a change of optical properties of ZnO–PDA composites as a shift of photoluminescence (PL) peaks and PL quenching. However, to date, the effect of the PDA layer on fundamental properties of ZnO–PDA nanostructures has not been studied. The presented paper reports on optical and surface properties of novel ZnO–PDA nanocomposites. PDA layers were chemically synthesized on ZnO nanostructures from different solution concentrations of 0.3, 0.4, 0.5 and 0.7 mg/mL. Structure, electronic and optical properties were studied by SEM, Raman, FTIR, diffuse reflectance and photoluminescence methods. The Z-potential of the samples was evaluated in neutral pH (pH = 7.2). The response of the samples towards poly-l-lysine adsorption, as a model molecule, was studied by PL spectroscopy to evaluate the correlation between optical and surface properties. The role of the PDA concentration on fundamental properties was discussed

Robust water repellent ZnO nanorod array by Swift Heavy Ion Irradiation: Effect of Electronic Excitation Induced Local Chemical State Modification

Tailoring the surface properties by varying the chemistry and roughness could be of interest for self-cleaning applications. We demonstrate the transformation of hydrophobic ZnO Nano rod (NR) array into superhydrophobic nature by changing the local chemical state and without altering the surface roughness by swift heavy ion (SHI) irradiation. The aligned ZnO NR arrays were irradiated using 150 MeV Ag ions with different fluences from 5E10 to 3E12 ions/cm2. The observed static water contact angles of ZnO NRs samples were 103° ± 3°, 152° ± 4°,161° ± 3°, 164° ± 2°, 167° ± 2°,154 ± 3° and 151° ± 2° for the pristine, ion fluencies of 1E11, 3E11, 5E11, 7E11, 1E12 and 3E12 ions cm−2, respectively. The change in local surface chemistry via formation of surface oxygen related defects due to electronic excitations induced by ion irradiation determine the water dewetting properties. It is found that surface oxygen related defects could be tuned by varying the fluence of the SHIs. Durability tests show that the SHI induced surface oxygen-deficient ZnO NRs have the stable superhydrophobic behavior for more than a year

Electrochemical Determination of Interaction between SARS-CoV-2 Spike Protein and Specific Antibodies

The serologic diagnosis of coronavirus disease 2019 (COVID-19) and the evaluation of vaccination effectiveness are identified by the presence of antibodies specific to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In this paper, we present the electrochemical-based biosensing technique for the detection of antibodies specific to the SARS-CoV-2 proteins. Recombinant SARS-CoV-2 spike proteins (rSpike) were immobilised on the surface of a gold electrode modified by a self-assembled monolayer (SAM). This modified electrode was used as a sensitive element for the detection of polyclonal mouse antibodies against the rSpike (anti-rSpike). Electrochemical impedance spectroscopy (EIS) was used to observe the formation of immunocomplexes while cyclic voltammetry (CV) was used for additional analysis of the surface modifications. It was revealed that the impedimetric method and the elaborate experimental conditions are appropriate for the further development of electrochemical biosensors for the serological diagnosis of COVID-19 and/or the confirmation of successful vaccination against SARS-CoV-2

Fabrication and characterization of ZnO/Graphene layered structures

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Cell and Tissue Response to Modified by Laser-induced Periodic Surface Structures Biocompatible Materials for Dental Implants

The use of femtosecond laser-induced periodic surface structures (LIPSS) for dental implants surface modification for improving cell adhesion and proliferation is reported. Results demonstrated higher response of cells on modified surface compared to untreated ones